// Copyright 2020 Proyectos y Sistemas de Mantenimiento SL (eProsima).
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ------------------------------------------------------------------
// Modification history:
// feature: Code style modification
// ------------------------------------------------------------------

#ifndef SRC_CPP_RTPS_PERSISTENCE_SQLITE3PERSISTENCESERVICESTATEMENTS_H_
#define SRC_CPP_RTPS_PERSISTENCE_SQLITE3PERSISTENCESERVICESTATEMENTS_H_

#include <string>
#include <sstream>

struct vbsSqlite3;

namespace evbs {
namespace ertps {
namespace rtps {

class SQLite3PersistenceServiceSchemaV1 {
 public:
    static constexpr const char* const writers_table =
        "guid TEXT,"
        "seq_num INTEGER CHECK(seq_num > 0),"
        "instance BLOB CHECK(length(instance)=16),"
        "payload BLOB,"
        "PRIMARY KEY(guid, seq_num DESC),"
        "FOREIGN KEY (guid)"
        "    REFERENCES writers_states(guid)";

    static constexpr const char* const readers_table =
        "guid text,"
        "writer_guid_prefix binary(12),"
        "writer_guid_entity binary(4),"
        "seq_num integer,"
        "PRIMARY KEY(guid, writer_guid_prefix, writer_guid_entity)";

    inline static std::string& writers_table_create_statement() {
        static std::string statement =
            std::string("CREATE TABLE IF NOT EXISTS writers(") + writers_table + ") WITHOUT ROWID;";
        return statement;
    }

    inline static std::string& readers_table_create_statement() {
        static std::string statement =
            std::string("CREATE TABLE IF NOT EXISTS readers(") + readers_table + ") WITHOUT ROWID;";
        return statement;
    }

    inline static std::string& database_create_statement() {
        static std::string statement = writers_table_create_statement() + readers_table_create_statement();
        return statement;
    }
};

class SQLite3PersistenceServiceSchemaV2 {
 public:
    static constexpr const char* const writer_histories_table = SQLite3PersistenceServiceSchemaV1::writers_table;

    static constexpr const char* const writer_states_table =
        "guid TEXT PRIMARY KEY,"
        "last_seq_num INTEGER CHECK(last_seq_num > 0)";

    static constexpr const char* const readers_table = SQLite3PersistenceServiceSchemaV1::readers_table;

    inline static std::string& writers_histories_table_create_statement() {
        static std::string statement =
            std::string("CREATE TABLE IF NOT EXISTS writers_histories(") + writer_histories_table + ") WITHOUT ROWID;";
        return statement;
    }

    inline static std::string& writers_states_table_create_statement() {
        static std::string statement =
            std::string("CREATE TABLE IF NOT EXISTS writers_states(") + writer_states_table + ") WITHOUT ROWID;";
        return statement;
    }

    inline static std::string& readers_table_create_statement() {
        static std::string statement =
            std::string("CREATE TABLE IF NOT EXISTS readers(") + readers_table + ") WITHOUT ROWID;";
        return statement;
    }

    inline static std::string& database_create_statement() {
        static std::string statement = std::string("PRAGMA user_version = 2;") + "PRAGMA foreign_keys = ON;" +
                                       writers_histories_table_create_statement() +
                                       writers_states_table_create_statement() + readers_table_create_statement();
        return statement;
    }

    inline static std::string& update_from_v1_statement() {
        static std::string statement =
            std::string("PRAGMA foreign_keys = ON;") +
            writers_states_table_create_statement()
            // Populate the writers_states with information available in the old writers table. Note
            // the assumption that last_seq_num would be the largest seq_num associated to a history
            // cache is not always true
            + "INSERT INTO writers_states SELECT guid, MAX(seq_num) FROM writers GROUP BY guid;" +
            writers_histories_table_create_statement()
            // Copy the contents of writers to the new table
            + "INSERT INTO writers_histories SELECT guid, seq_num, instance, payload FROM writers;"
            // Remove the old table, since it is no longer required
            + "DROP TABLE writers;"
            // Once the upgrade has succeded add the version number
            + "PRAGMA user_version = 2;";
        return statement;
    }
};

class SQLite3PersistenceServiceSchemaV3 {
 public:
    static constexpr const char* const writer_histories_table =
        "guid TEXT,"
        "seq_num INTEGER CHECK(seq_num > 0),"
        "instance BLOB CHECK(length(instance)=16),"
        "payload BLOB,"
        "related_sample_guid TEXT,"
        "related_sample_seq_num,"
        "source_timestamp INTEGER,"
        "PRIMARY KEY(guid, seq_num DESC)";

    static constexpr const char* const writer_states_table = SQLite3PersistenceServiceSchemaV2::writer_states_table;

    static constexpr const char* const readers_table = SQLite3PersistenceServiceSchemaV2::readers_table;

    inline static std::string& writers_histories_table_create_statement() {
        static std::string statement =
            std::string("CREATE TABLE IF NOT EXISTS writers_histories(") + writer_histories_table + ") WITHOUT ROWID;";
        return statement;
    }

    inline static std::string& writers_states_table_create_statement() {
        static std::string statement =
            std::string("CREATE TABLE IF NOT EXISTS writers_states(") + writer_states_table + ") WITHOUT ROWID;";
        return statement;
    }

    inline static std::string& readers_table_create_statement() {
        static std::string statement =
            std::string("CREATE TABLE IF NOT EXISTS readers(") + readers_table + ") WITHOUT ROWID;";
        return statement;
    }

    inline static std::string& database_create_statement() {
        static std::string statement = std::string("PRAGMA user_version = 3;") + "PRAGMA foreign_keys = OFF;" +
                                       writers_histories_table_create_statement() +
                                       writers_states_table_create_statement() + readers_table_create_statement();
        return statement;
    }

    //! Generates a temporary table with the default values of the different
    // library types managed by the database
    static bool database_create_temporary_defaults_table(vbsSqlite3* db);

    inline static std::string& update_from_v2_statement() {
        // note that the statement relies in the existence of the TEMP.Defaults table generated
        // via database_create_temporary_defaults_table() call
        static std::string statement =
            // foreign_keys led to sluggish operation
            std::string("PRAGMA foreign_keys = OFF;")
            // substitute the old writers_histories table
            + "ALTER TABLE writers_histories RENAME TO old_writers_histories;" +
            writers_histories_table_create_statement() +
            "INSERT INTO writers_histories \
                     SELECT \
                         old.guid, \
                         old.seq_num, \
                         old.instance, \
                         old.payload, \
                         def_guid.Value, \
                         def_sn.Value, \
                         def_ts.Value \
                     FROM old_writers_histories AS old, TEMP.Defaults AS def_guid, TEMP.Defaults AS def_sn, TEMP.Defaults AS def_ts \
                         WHERE def_guid.Name = 'GUID_t' AND def_sn.Name = 'SequenceNumber_t' AND def_ts.Name = 'rtps::Time_t'; \
                   DROP TABLE old_writers_histories;"
            // Once the upgrade has succeded add the version number
            + "PRAGMA user_version = 3;";
        return statement;
    }

    static const char* default_guid();

    static uint64_t default_seqnum();

    static int64_t now();
};

} /* namespace rtps */
} /* namespace ertps */
} /* namespace evbs */

#endif  // SRC_CPP_RTPS_PERSISTENCE_SQLITE3PERSISTENCESERVICESTATEMENTS_H_
